9-03300 Concrete.pdf

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SECTION 03300

CONCRETE

PART 1 GENERAL

1.1 WORK INCLUDED

A. Furnish all labor, supervision, materials and equipment to do all plain and reinforced concrete work shown on drawings or herein specified. All work shall be done in accordance with ACI 318 "Building Code Requirements for Reinforced Concrete" and ACI 301, "Specification for Structural Concrete for Buildings".

Unless otherwise specified, all references to standards and codes shall be the latest revision to date.

1.2 SUBMITTALS

A. Submit information on concrete mix design showing composition of all mixes.

Show materials, admixtures, ratios, compressive strength, slump and mix design in accordance with ACI 318.

B. Laboratory Test Results:

1. Testing laboratory shall submit the results of tests performed on materials used in the concrete.

2. Concrete Mix Design:

a. Testing laboratory shall submit test results of laboratory trial batches run to determine concrete mix proportions if such trail batches are run.

3. Testing laboratory shall submit results of field tests and laboratory tests performed on concrete during construction. Number and frequency of tests shall be as specified in Part 3, Paragraph 3.04. Results from 7-day test shall be submitted as soon as they are available.

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PART 2 PRODUCTS

2.1 PORTLAND CEMENT

A. Portland cement shall be Type I conforming to ASTM-C150, "Standard Specifications for Portland Cement".

2.2 FINE AND COARSE AGGREGATE

A. Fine and coarse aggregates shall conform to ASTM-C33, "Standard Specifications for Concrete Aggregates".

2.3 WATER

A. Water shall be potable.

2.4 ADMIXTURES

A. General:

1. Admixtures shall be free of all chlorides.

B. Water Reducing Type:

1. Conform to ASTM C494, Type A.

2. Conform to manufacturer's recommendations for use.

3. Technical assistance of the manufacturer's field representative shall be furnished upon request.

C. Air-Entraining Type:

1. Air entrainment of concrete shall be 6%.

2. Conform to ASTM C260.

3. Conform to manufacturer's recommendations for use.

4. Technical assistance of the manufacturer's field representative shall be furnished upon request.

5. Testing of air-entraining admixtures shall conform to ASTM C233.

D. Other Admixtures: Used only with Engineer's written concurrence.

1. Water Reducing, Retarding Type: Conform to ASTM C494, Type D.

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2.5 CONCRETE QUALITIES

A. Compressive Strength:

1. Minimum 28 day compressive strength = 3,750 psi for all construction unless otherwise specified.

B. Slump: per ACI 318.

C. Air content: per ACI 318.

D. All concrete shall contain entrained air in accordance with ACI 318.

2.6 MIX PROPORTIONS

A. Concrete shall conform to ACI 211.1, "Standard Practice for Selecting Proportions for Normal, Heavyweight and Mass Concrete" and ACI 304R-85, "Recommended Practice for Measuring, Mixing, Transporting and Placing Concrete".

B. Mix proportions for all concrete unless otherwise specified shall be selected preferably on the basis of field experience, but in the case where sufficient or suitable strength test data is not available, concrete shall be proportioned on the basis of laboratory trial mix design.

C. There shall be adequate workability and proper consistency to permit the concrete to be worked readily into the forms and around reinforcement under the conditions of placement to be employed without excessive segregation or bleeding.

D. Ready-Mix concrete is used and shall conform to ASTM-C94, "Standard Specifications for Ready-Mixed Concrete".

2.7 METAL REINFORCEMENT

A. Metal reinforcement bars shall conform to ASTM-A615, Grade 60 "Standard Specifications for Concrete Reinforcement".

B. Welded wire fabric shall conform to ASTM A185, "Standard Specification for Welded Steel Wire Fabric for Concrete Reinforcement".

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PART 3 EXECUTION

3.1 MIXING AND PLACING CONCRETE

A. Preparation of Equipment and Place of Deposit:

1. Before concrete is placed, all equipment for mixing and transporting the concrete shall be clean, all debris and ice shall be removed from the spaces to be occupied by the concrete, and the reinforcement shall be thoroughly clean of ice or other deleterious coatings.

2. Water shall be removed from the place of deposit before concrete is placed or unless otherwise permitted by the Engineer.

3. All laitance and other unsound material shall be removed from hardened concrete before additional concrete is placed.

B. Mixing of Concrete:

1. Concrete Mixed at Plant off Jobsite:

a. Water may not be added to concrete after truck has left the plant.

b. Ready-Mixed concrete shall be produced and delivered conforming to ASTM C94 as applicable.

c. Contractor shall furnish Engineer with a concrete delivery ticket for each load of concrete. The ticket shall have the following information recorded:

- Ticket number

- Time batched

- Time arrived on Jobsite

- Amount of concrete (by volume)

- Mix number

C. Conveying:

1. Concrete shall be conveyed from the mixer to the place of final deposit by methods which will prevent the segregation or loss of materials.

2. Conveying equipment shall be capable of providing a supply of concrete at the site of placement without interruptions sufficient to permit loss of plasticity between successive increments.

3. Aluminum conveying equipment shall not be used.

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D. Depositing:

1. Concrete shall be deposited as nearly as practicable in its final position to avoid segregation due to rehandling or flowing. The concreting shall be carried on at such a rate that the concrete is plastic at all times and flows readily into the spaces between the bars. No concrete that has partially hardened or has been contaminated by foreign materials shall be deposited in the structure, nor shall retempered concrete or concrete which has been remixed after initial set be used unless approved by the Engineer.

2. After concreting is started, it shall be carried on as a continuous operation until the placing of the panel or sections is completed except as permitted or prohibited by ACI 318. The top surface of vertically formed lifts shall be generally level.

3. Consolidation of Concrete:

a. Consolidate concrete in conformance with ACI 309, "Recommended Practice for Consolidation of Concrete".

4. Time Requirements

a. Place concrete at a sufficient rate to assure that lifts below have not taken initial set before fresh concrete is deposited.

b. Concrete which has partially set shall not be retempered but shall be discarded.

E. Curing:

1. Concrete shall be cured in accordance with ACI 308, "Standard Practice for Curing Concrete". Method and duration of curing are subject to approval by the Engineer.

F. Cold Weather Requirements:

1. Concreting shall be done in accordance with ACI 306R "Recommended Practice for Cold Weather Concreting". Recommendations shall be considered as mandatory.

G. Hot Weather Requirements:

1. Concreting shall be done in accordance with ACI 305R, "Recommended Practice for Hot Weather Concreting".

Recommendations shall be considered as mandatory.

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3.2 DETAILS OF REINFORCEMENT

A. Surface Conditions of Reinforcement:

1. Metal reinforcement at the time concrete is placed shall be free from mud, oil, or other coatings that adversely affect bonding capacity.

B. Splices:

1. All rebar splices shall be Class B, unless otherwise indicated.

3.3 FINISHES

A. Concrete finishes shall be as specified and as defined in ACI 301.

3.4 TESTING

A. Laboratory Testing of Materials for Use in Concrete:

1. An approved independent testing laboratory shall be selected and paid by the Contractor to perform all required laboratory tests of materials proposed for use in the production of concrete and to determine mix proportions when laboratory trial batches are required.

2. The laboratory shall report the results of the testing and mix designs to the Engineer.

3. Contractor shall deliver representative samples of all proposed concrete materials to the laboratory for testing.

B. Field Testing of Concrete and Making of Concrete Test Cylinders

1. Testing laboratory shall furnish test equipment, test cylinder molds, and trained personnel to perform all required field tests, make the required concrete test cylinders and deliver test cylinders to the testing laboratory.

The prescribed tests shall be made in the presence of or with the concurrence of the Engineer.

2. Concrete sampling for tests and cylinders shall conform to ASTM C172.

3. Perform the following tests:

a. Prepare test cylinders conforming to ASTM C31, with not less than one set of cylinders (six cylinders) from each day's placement or for each 100 cubic yards or fraction thereof.

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b. Slump test conforming to ASTM C143.

c. Air content test conforming to ASTM C231.

d. Discard concrete used for slump and air tests.

e. Slump and Air test results shall be included in the Cylinder Test

Reports.

C. Laboratory Testing of Concrete During Construction:

1. An independent testing laboratory shall be selected and paid by the Contractor to perform the required laboratory tests and statistical evaluations of the concrete being used in the work.

2. Laboratory shall cure and test concrete cylinders conforming to ASTM C31, and C39, testing three cylinders at seven days of age, of age and two at 28 days of age. Two be reserved for possible further testing.

3. Testing laboratory shall provide Contractor, Engineer, and Owner with copies of the test reports.

4. Should the statistical data indicate an unacceptable combination of average strength and standard deviation, Contractor shall take immediate corrective action.

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